Rotary Transmission Leadthrough Provided with a Gas Return Line

ABSTRACT

The aim of the invention is to provide a simple and compact design of a rotary transmission leadthrough ( 10 ) provided with a gas return line, in particular for filling a vehicle fuel tank comprising a rapid-action connection coupling ( 1 ), which is connected to the supply line ( 12 ) and to a return line ( 42 ). According to the invention, the supply line ( 12 ) and the return line ( 42 ) are arranged in a coaxial manner in relation to each other.

The invention relates to a rotary transmission leadthrough with a gasreturn line, especially for filling a vehicle gas fuel tank, inaccordance with the features in the preamble of claim 1.

A secure and quick-connecting transmission of a fluid from a pressuresource such as a natural-gas refuelling installation to a vehicle is tobe achieved with such rotary transmission leadthroughs. Especiallyimportant aspects in this respect are the simple and easy-to-useoperation, so that even in the case of high refuelling pressures of 200bars and more easy handling is enabled, especially in connection withrapid-action connection couplings. The connection of such couplings mayrequire a high amount of force in the case of large throughput crosssections (e.g. in the case of refuelling buses) as a result of thetwisting of the connecting hose. Moreover, the control lever can thus bebrought to an unfavourable position during the insertion of thecoupling, so that single-hand operation is hardly possible.

In order to remedy such problems, a rotary transmission leadthrough inconjunction with a rapid-action connection coupling was described in WO98/05898 of the applicant, with the rapid-action connection couplingcomprising a housing with a fluid inlet and a fluid outlet and severalvalves in order to ensure secure sealing of the rapid-action connectioncoupling until the connection has been fully established. Forcompensating the twisting of the connecting hose a rotary transmissionleadthrough was proposed which is integrated in the rapid-actionconnection coupling and also comprises a gas return via a second line.The lines proposed therein are relatively complex from a constructionalviewpoint because respective connections such as union nuts and the likeneed to be provided on the rotary transmission leadthrough and on thehose side.

The invention is therefore based on the object of providing a rotarytransmission leadthrough with gas return line of the kind mentionedabove, especially for use in a rapid-action connection coupling, whichin combination with a simple configuration offers an especially compactdesign.

This object is achieved by a rotary transmission leadthrough with a gasreturn line according to the features of claim 1. Preferred furtherdevelopments of the invention are the subject matter of the sub-claims.

The proposed rotary transmission leadthrough with a gas return line isespecially suitable for use with a rapid-action connection coupling forrefuelling with gas, with an especially simple and compact configurationbeing obtained because the return line is arranged in a coaxial mannerto the supply line and thus only one hose is visible. When connecting ordetaching the rapid-action connection coupling, mutual twisting of theconnection hose and the gas return line is securely prevented,especially for the preferred embodiment of the invention for fillingvehicle gas tanks.

Moreover, the screw joints of the supply line are advantageously withinthe return line and are thus securely encapsulated, so that in the eventof any occurring leakages in the high-pressure screw joints or thesupply line any gas leaking by diffusion can securely be removed withinthe return line. This is especially important for reasons ofenvironmental protection because thus no gas volume is lost.

Moreover, handling is also facilitated because the supply line as wellas the gas return line are uncoupled from each other in the direction oftorsion, so that no excessive application of force is required. Noticemust be taken that the proposed rotary transmission leadthrough issuitable for a large variety of couplings and connections. The rotarytransmission leadthrough can also be arranged as a part forretrofitting, especially for long supply lines in the form of a separatecomponent.

As a result of the rotary sleeve which is preferably integrated in therapid-action connection coupling, complete rotational mobility of therapid-action connection coupling is thus achieved relative to the supplyline at any pressure level, so that twisting of the connection hose andthe coaxial gas return line is avoided. The relative twistability of thetwo coaxial sleeves relative to each other is ensured, so that therapid-action connection coupling can be connected without any majorapplication of force.

An embodiment of the invention is now explained and described in closerdetail by reference to the enclosed drawings, wherein:

FIG. 1 shows a side view of a partially shown rapid-action connectioncoupling with an integrated rotary transmission leadthrough and a gasreturn line in a half-section, and

FIG. 2 shows a modified embodiment of the supply line.

FIG. 1 shows a preferred embodiment of a rotary transmission leadthrough10 for use in combination with a rapid-action connection coupling 1indicated on the left side here, which coupling can be coupled to aconnection nipple (not shown). The rapid-action connection coupling 1comprises a tubular housing 11 with a central fluid passage (see doublearrow), with the supply of fluid occurring here from the right via asupply line 12 which is used for further conducting the fluid to betransferred to the left to the connection nipple. The supply line 12comprises a connection adapter 14 which is pressed and/or screwed ontothe hose end of the supply line 12. A high-pressure screw joint 25 isadjacent thereto, which joint leads to a rotary sleeve 24 and is sealedaccordingly within the rotary transmission leadthrough 10. The tubularsupply line 12, the connection adapter 14, the screw joint 25 and therotary sleeve 24 inserted into the rotary transmission leadthrough 10are arranged accordingly by being adapted to the respectivelytransmitted fluid, especially to the desired supply pressure values,leadthrough cross sections, etc.

Several grips (not shown) which are arranged in tubular form areprovided in housing 11 and are used for insertion on the connectionnipple in order to latch the rapid-action connection coupling 1 to thesame. This arrangement is shown for example in the aforementioned WO98/05898, so that a further description can be omitted. It merely needsto be mentioned that within the housing 11 a venting passage E in theform of an axial venting bore 13 is arranged within the housing 11,which venting passage leads to a vent valve and extends parallel to thecentral fluid passage (cf. double arrow) of the rapid-action connectioncoupling 1. An annular collar 26 is further provided on the rotarysleeve 24, which collar can be twisted relative to the housing 11 bymeans of a slide disk 29 and/or a roller bearing (cf. FIG. 2). Acounter-sleeve 27 rests on the other face side of the annular collar 26which is clamped with a union nut 28 against the housing 11. A ring 30is provided around said union nut 28 which on its inside circumferencecomprises several axially extending slits 31.

When the vent valve is now opened for uncoupling, gas flows for pressurereduction along the vent passage E via the vent bore 13, an intermediateor compensating cavity 18, the said slits 31 and an annular cavity 38 tothe right to the recirculation R, as is indicated with the dot-dashline. The annular cavity 38 is sealed like the entire vent passage E bygaskets 16 and 17 to the outside, so that the gas can only flow into theannular gap between the supply line 12 and the coaxial return line 42 torecirculation R (e.g. a filling station).

The return line 42 is held within the union nut 39 which seals theannular cavity 38 and comprises a connecting adapter 39 which ispreferably arranged as a press fitting in order to ensure high tensileand tearing strength of the return line. As a result, relatively highgas pressures can be realized towards the recirculation side R. This isespecially advantageous when the high-pressure screw joint 25 or thesupply line 12 should have a leak. In this case, any optionally leakinggas can be removed within the return line 42 and cannot escape to theoutside.

When fluid is supplied, the pressure can be applied to the face side ofthe rotary sleeve 24 or the slide disk 29 which face here to the left,so that a considerable axial force on the rotary sleeve 24 would beobtained in the case of high pressure values. For compensating purposes,a leadthrough (not shown) from the compensating cavity 18 is providedhere within the rotary leadthrough 10, preferably in the form of anoblique or radial bore, so that the rotary sleeve 24 remainssubstantially free from axial forces and thus easy to twist.

As mentioned above, the vent valve is opened during the uncoupling ofthe rapid-action connection coupling 1. As a result, any still applyingpressure medium flows via the vent bore 13 which is aligned parallel tothe central fluid passage in the housing 11 or the rotary leadthrough 10and the slots 31 (or similar bores) and the annular cavity to the returnline 42. The annular cavity 38 is sealed by gaskets 16 in the cornerregion for example between the connecting adapter 40 and the union nut39. The rotary sleeve 24 connected to the supply line 12 can be twistedrelative to each other like the return line 42 and is connected relativeto the stationary housing 11 in a twistable manner within the rotaryleadthrough 10, so that the return line 42 and the fluid line 12extending parallel thereto cannot twist with each other.

Notice must be taken that the rotary transmission 10 which is integratedhere in the rapid-action connection coupling 1 can also be arranged as aseparate component, especially a part for retrofitting existingcouplings. In this case, the rotary leadthrough 10 for the two lines 12and 42 extending coaxially relative to each other would endapproximately along the compensating cavity 18, with the housing 11situated opposite of the rotary sleeve 24 then being provided with aseparate line connection.

As already mentioned above, relatively high pressure values can berealized in the return line 42, so that the modified arrangementaccording to FIG. 2 is also possible, i.e. the two lines 12 and 42extending coaxially relative to each other can be used in a reversemanner in their direction of flow. In this case, the return conductionof the vented medium occurs towards the recirculation side R via thecentral line 42, whereas the supply from the filling side which is tothe right in this case occurs via an oblique bore Z in the supply line12 which is arranged here in an annular manner about the line 42. Thepressure medium is guided from there again via an oblique bore Z to thecentral fluid passage in the region of the rotary sleeve 24 in order toopen into the connection coupling 1 according to the double arrow inFIG. 1. Components with the same function are provided with identicalreference numerals as in FIG. 1.

Venting occurs in FIG. 2 as in FIG. 1 via vent bores 13 and an annularcavity 38 around the rotary sleeve 24. In this region of the rotaryleadthrough 19, i.e. within the ring 30, an oblique bore E is providedwhich guides the vented medium into the central return line 42. At thesevering point indicated here between the right and left half of thehigh-pressure hose, the direction of the flow of the medium is indicatedwith arrows. Such a high-pressure hose can have a length of severalmeters. At the right side here (filling station side), an adapter A isattached, with the return line 42 leading again via a (second) obliquebore E in adapter A to the recirculation side R. Notice must be takenthat a similar adapter A can also be attached to the right hose end ofthe coaxial lines 12 and 42 of the embodiment in FIG. 1. The outercovering hose is thus used in both embodiments also for the protectionof the coaxial central line. The annular cavity around the central linecan be used either for supplying as well as for removing in a controlledmanner the gases on the recirculation connection R of adapter A.

1. A rotary transmission leadthrough with a gas return line, especiallyfor filling a vehicle gas fuel tank with a rapid-action connectioncoupling which is connected with a supply line and a return line,wherein the supply line and the return line are arranged in a coaxialmanner in relation to each other.
 2. A rotary transmission leadthroughaccording to claim 1, wherein that the supply line and the return lineeach comprise connection adapters which are arranged coaxially inrelation to each other.
 3. A rotary transmission leadthrough accordingto claim 2, wherein the connection adapters are arranged within theunion nut which encloses an outwardly sealed annular cavity.
 4. A rotarytransmission leadthrough according to claim 3, wherein a rotary sleeveopens centrally into the annular cavity.
 5. A rotary transmissionleadthrough according to claim 4, characterized in that the supply lineis connected to the rotary sleeve with a high-pressure screw joint.
 6. Arotary transmission leadthrough according to claim 4 or 5, wherein therotary sleeve comprises an annular collar on the circumferential sidewhich is rotatable relative to the housing of the rapid-actionconnection coupling.
 7. A rotary transmission leadthrough according toclaim 4, wherein the rotary sleeve with a union nut and a counter-sleeveis rotatably connected with the housing.
 8. A rotary transmissionleadthrough according to claim 7, wherein a ring is rotatably held onthe union nut which comprises slits on its inner circumference for gasrecirculation.
 9. A rotary transmission leadthrough according to claim 7or 8, wherein the slits are opposite of a vent bore in the housing andoptionally a compensating cavity.
 10. A rotary transmission leadthroughaccording to claim 3, wherein that the annular cavity and thecompensating cavity are sealed towards the outside by means of gaskets.11. A rotary transmission leadthrough according to claim 1, wherein therotary sleeve is arranged in the inlet region of a rapid-actionconnection coupling.
 12. A rotary transmission leadthrough according toclaim 1, wherein the return line is arranged centrally within the supplyline.
 13. A rotary transmission leadthrough according to claim 12,wherein at least one oblique bore leads radially to the outside from thecentral return line, especially on an adapter towards the return lineside and/or towards an annular cavity on the rotary transmissionleadthrough.